• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 1998년도 강연회 및 연구개발 발표회 논문집
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• pp.63-72
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• 1998

This study Is on the performance prediction and design of sirocco fan. Slip coefficient is very important factor for the performance analysis of centrifugal-type fan. Because generally used slip coefficient equations of backward curved centrifugal fan are not appropriate for forward curved sirocco fan, in this study a proper slip coefficient equation for sirocco fan is suggested. Using this equation performance prediction program for sirocco fan is composed and also included the total noise prediction that include turbulent noise at the fan Inlet and boundary layer noise. A comparison between the values obtained from performance prediction program and experimental values shows that the program predicts the sirocco fan performance in a practical rate.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.197-202
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• 2014

Floor Impact Noise is a structure-borne noise which is mainly caused by vibration of concrete slabs. The majority of previous studies have focused on investigating performance of absorbing sheets on the reduction of floor impact noise. But absorbing sheets do not efficiently reduce heavy-weight floor impact noise level because it cannot absorb slab vibration, which is the fundamental noise source. In this study, double-floor system was developed in order to reduce floor impact noise level in residual buildings. This floor system reduces heavy-weight impact noise level by reducing vibration response at the center of slab, which has maximum amplitude in the 1st vibration mode. In order to identify the performance of the double-floor system, experiments were planned. Primary test parameters are span of double floor, arrangement and types of absorbing sheets.

• 조명전기설비학회논문지
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• 제23권8호
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• pp.110-115
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• 2009

최근 생활수준의 향상과 세계적인 녹색성장 정책으로 환경에 대한 관심이 고조되어, 전력분야에서도 환경친화적인 설비가 요구되어 지고 있다. 이에 따라 전력용 변압기 냉각팬도 날개형상과 배치형태를 개선한 저소음 냉각팬이 개발되었으며, 일반 전력용 변압기 및 저소음 변압기에 적용될 예정이다. 냉각팬은 낮은 소음레벨 뿐만 아니라 우수한 냉각성능의 확보가 필수적이다. 그러나 현재까지 저소음 냉각팬의 소음레벨과 냉각성능에 대한 검토가 이루어지지 않은 실정이다. 따라서 본 논문에서는 소음레벨 측정과 풍량 측정 실험을 통해 저소음 냉각팬의 성능을 분석하였다. 또한 저소음 냉각팬을 적용한 전력용 변압기의 온도상승 시험을 통하여 냉각성능을 검증하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.754-757
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• 2005

Aircraft noise is the serious problem for inhabitants near an air force base. Noise by ground test of aircraft, however, can be minimized through test room construction. In this study, environmental effects of the noise by aircraft ground test were investigated by experiments under the standard act and by performance, prediction of the Hush house, constructed for the noise reduction.

• 한국진공학회지
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• 제8권3B호
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• pp.315-321
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• 1999

In this paper, the SEM image processing system based on PC is designed, and a new noise reduction filtering algorithm is proposed. The SEM image obtained in semiconductor processing line is sensitive to noise, the weighted-D filter can remove uniform and Gaussian noise effectively, but can not remove impulse noise properly, A new improved filtering algorithm is proposed to reduce mixed-noise. The performance of the proposed filter is quantitatively evaluated by use of the normalized mean square errors (NMSE). The experimental results show that the performance of the proposed filter is obtained between 0.96 and 2.5 times better than that of weighted-D filter in NMSE evaluation.

• 한국소음진동공학회논문집
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• 제17권12호
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• pp.1139-1144
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• 2007

The use of noise barrier is being increased to reduce the environmental noise in these days. Also, many noise reducers installed at the top of noise barrier are developed for improving the efficiency of noise reduction. So we evaluate the performance of the noise reducers and compare the results among the others. Results of field tests show that the insertion loss due to the noise reducers is up to 10.6 dB.

• 전기학회논문지P
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• 제62권4호
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• pp.192-197
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• 2013

Road traffic noise barriers being used to reduce the noise, but the city surroundings inhibition, ecosystem disturbance, and it is difficult to maintain. Can enhance or complement the existing noise barrier performance, so that it is necessary to develop an electronic noise-reduction system In this paper, we proposed an electronic road noise reduction devices to reduce road noise for a DSP-based signal processing and analog signal input-output controller. In order to verify the control performance, we performed noise reduction experimentation of ANC by filtered-X LMS algorithm and traffic noise signal injection. The controller is equipped with noise reduction algorithms were tested on the characteristics of directional and omnidirectional speaker.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.570-574
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• 2013

The use of noise barrier is being increased to reduce the environmental noise in these days. Also, many noise reducers installed at the top of noise barrier are developed for improving the efficiency of noise reduction. So we evaluate the performance of the noise reducers and compare the results among the others. Results of field tests show that the insertion loss due to the noise reducers is up to 10.6 dB.

• 한국유체기계학회 논문집
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• 제1권1호
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• pp.32-40
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• 1998

Aerodynamic performance of a cooling fan of driving motor was enhanced modifying the vane-shroud configuration. Performance of a target model was evaluated to obtain baseline data. The aerodynamic performance and sound pressure level were tested and measured with different numbers of vane of increased length. The tested models show high and stable performance and low values of specific noise level. The long vane-shroud structure induces more stable through flow and decreases the tip leakage flow, which contributes to the increases of performance and efficiency. The sound pressure level increases for the modified model, however, specific noise level decreases.

• 한국통신학회논문지
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• 제29권4C호
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• pp.485-493
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• 2004

파장/시간 2차원 광 코드 분할 다중화 방식 (OCDMA)에 대한 시스템의 성능은 신호와 다중 사용자 간섭 사이에 비트 잡음이 일어나는 것에 의해 제한된다. 본 논문에서는 OCDMA시스템에서 비트 잡음에 대한 영향을 분석한 것으로써 비트 잡음이 있을 때와 비트 잡음 없을 때의 OCDMA성능을 분석하였으며 이를 극복하기 위한 방법으로 OHL (Optical Hard-Limiter)를 수신단에 포함하는 방법을 제안하고 이 때의 성능평가를 수행하였다. 성능 평가를 위해 사용되는 코드는 대칭적이고 비대칭적인 prime-hop 2차원 코드를 사용하였다. 분석결과 코드가 대칭인 경우 성능은 비트잡음이 있을 때 OHL가 있는 경우와 제안한 OHL을 사용한 경우 약 3.5배의 성능 향상을 보이며 비트 잡음이 없는 경우 OHL이 없는 경우와 제안한 OHL이 있는 경우 1.5배의 성능 향상을 확인 할 수 있었다.